基于相关法的低采样率超声水表时延估计方法

针对当前超声水表中相关法时间分辨率只能达到采样周期的问题,提出了一种基于相关法的低采样率超声水表时延估计方法.首先,研究了超声水表中所能达到的最大时间延迟;其次,讨论了相关法在超声水表当中的具体应用及插值算法对于提高流量测量精度的作用;最后,利用MATLAB软件对算法进行仿真评估了实际噪声条件下算法能达到的时延估计精度并搭建流量计量系统证明算法的有效性.仿真结果表明,在超声换能器频率为1 MHz、采样频率为4 MHz的情况下,时延估计的平均绝对误差在百皮秒内.表明该算法能在较低的采样频率下实现高精度的时延估计,在时延估计精度上比传统相关法更具有优越性.

Low-sampling rate ultrasonic water meter time delay estimation method based on correlation method

Aiming at the problem that the temporal resolution of correlation method in ultrasonic water meter can only reach the sampling period, a time delay estimation method based on correlation method with low sampling rate is proposed. Firstly, the maximum time delay in ultrasonic water meter is studied. Secondly, the specific application of correlation method in ultrasonic water meter and the function of interpolation algorithm to improve the accuracy of flow measurement are discussed. Finally, MATLAB software is used to simulate the algorithm and evaluate the estimation accuracy of the algorithm under the condition of actual noise, and the flow measurement system is built to prove the effectiveness of the algorithm. The simulation results show that the average absolute error of time delay estimation is within 100 picoseconds when the frequency of ultrasonic transducer is 1 MHz and the sampling frequency is 4 MHz. It is shown that the proposed algorithm can achieve high precision delay estimation at low sampling frequency and is superior to the traditional correlation method in the accuracy of delay estimation.